Microstat^®He2 short working distance liquid helium optical cryostat

Helium cooled optical cryostat for microscopy with the lowest helium consumption and fastest cooldown on the market!

New look, new features, new accessories, new software

Very short working distance
2.2 - 500 K temperature range
Low liquid helium comsumption - as little as 0.45 l/h using a low loss LHe transfer tube
Rapid cooldown: 4.2 K in less than 10 minutes!
A compact, light weight system - only 1.8 kg
Choice of reflectance (one window) or transmission (two windows) configuration
Supplied with the new MercuryiTC temperature controller

Ideal for use with microscope-based spectrometers.

A unique feature of the MicrostatHe2 is its inter-changeable "cold unit" which allows the same core cooling unit to be fitted into a MicrostatHe2 Rectangular Tail or an OptistatCF-V outer body for huge experimental flexibility.

Specifications
System options
Operation
Applications
New accessories

Layout and dimensions

MicrostatHe short working distance liquid helium optical cryostat layout and dimensions

Optical specifications

	Window thickness
	0.5 mm	1.5 mm
Clear access diameter	10 mm	25 mm
Sample holder to window top surface	4.5 mm	5.5 mm
Angle of admittance (to surface of sample holder at centre)	102°	144°
Max sample thickness	5 mm	5 mm
Max sample diameter	20 mm	20 mm

All dimensions are approximate and relate to the top window with plain sample holder in central position

Product specifications

	Description
Cooling medium	Liquid helium (can be used with liquid nitrogen)
Operating temperature range	2.2 K to 500 K (with EPS40 pump)
	3.2 K to 500 K (with GF4 pump)
Temperature stability	± 0.1 K
Helium consumption	< 0.45 lhr-1 (at 4.2 K)
Cool down time	< 10 minutes from ambient to 4.2 K with transfer tube cold
Sample holder drift at constant temperature	±1 µm (typical – see note 1)*
Sample holder vibration	0.1 µm (typical – see note 2)*
Sample window material	Spectrosil B fused quartz
Other materials available on request
Standard temperature sensor	3-point calibrated rhodium iron (see note 3)
Sample change time	30 min (approx)
Weight	1.8 kg

* Approximate measurement. The stability is neither measured nor guaranteed and will be dependent upon the system’s final configuration and the environment that the equipment is used in.

1. Thermal drift of the sample position was measured after the cryostat temperature had stabilised for half an hour at base temperature. At temperatures above 4.2 K the time to reach thermal equilibrium is considerably longer. Typical values for the drift have been measured tube 1 µm in 5 minutes below 100 K and 1 µm in 1 minute above 100 K.

2. Vibration levels were measured with the cryostat, LLT600/13 transfer tube and a diaphragm pump. Room temperature measurements showed that in all directions the displacement due to mechanical vibration for frequencies greater than 500 Hz is negligible. For frequencies below 500 Hz vibration levels are less than 0.1 µm.

3. The cryostat is supplied with a temperature sensor mounted in the heat exchanger. The sample holder is in thermal contact with the heat exchanger. The temperature difference between the sample position and the heat exchanger has been measured to approximately 0.4 K.

Windows

A wide range of window materials can be fitted to the MicrostatHe2 - see the 'Windows for optical cryostats guide' in Downloads And Links
Standard window thickness is 0.5 mm with clear 10 mm access diameter. We also offer an option for a 25 mm access diameter window with a thickness of 1.5 mm
Transmission experiments use an alternative bottom flange with a second window fitted and a transmission sample holder
Additional or replacement window flanges available via the Oxford Instruments Direct - Cryospares® on-line catalogue

Temperature controller

MercuryiTC intelligent Cryogenic Environment Controller

Pump options

A simple GF4 oil-free vane pump is supplied for operation to 3.2 K
Lower temperatures to 2.2 K use a single-stage EPS40 rotary pump

See also the MicrostatHiRes2 for a high-stability, low-vibration microscopy cryostat with sample in vacuum.

The MicrostatHe2 optical cryostat works on a continuous flow (CF) principle using an oil-free pump to draw liquid helium from a storage vessel along a transfer tube to the heat exchanger ("pull mode"). Temperature control is achieved by a combination of manual or automatic helium flow control and power dissipated in an electrical heater, regulated using a temperature controller.

The cryostat can also be used in "push mode", in which case the flow of liquid helium is generated by pressurising the storage dewar. The advantage is that the need for a gas flow pump is removed, eliminating the vibration and noise generated by the pump, and reducing the system cost.

Microstat family continuous flow optical cryostat operating principle

The MicrostatHe2 can also be operated with liquid nitrogen (LN2) cooling for measurements down to 80 K.

Research Areas	Technique (optical microscopy & microscope based techniques
Study of molecular bonds in crystal lattices	Micro-FTIR
Study of molecular energy levels	Micro-Raman scattering and inelastic light scattering
Studies of Quantum Dot structures in AS/GaHS	Micro-luminescence
Semiconductors Quantum systems dots/wires/wells	Micro-Photo luminescence Micro-luminescence

NEW Transfer tube - It plays an important part in the overall helium consumption and base temperature capability of helium cooled cryostat.

Oxford Instruments Low Loss Transfer tubes (LLT) use the cold gas exiting the cryostat to cool the shields surrounding the incoming liquid within the trasfer tube. As a result, the consumption of our cryostats is the lowest on the market, dramatically reducing your running costs.

We can also offer an extra flexible transfer tube for those with restricted space in their labs. Please note that as this does not use the gas cooled mechanism, helium consumption will be higher that for the LLT range. However it will be well suited to those who need lightweight and more flexible transfer tube.

NEW Gas flow controller - The new VC-U gas flow controller now includes the nitrogen and helium flow meters as standard.

NEW Intelligent cryogenic environment controller - Easy monitoring and control of the sample stage. The MercuryiTC controller combines several instruments into one allowing temperature control at the heat exchanger and glas flow control as well as an extra sensor channel for thermometry measurement directly at the sample stage. Everything can be accessed through touch screen front panel and remotely via Labview compatible Oxsoft IDK software.

Example MicrostatHe2: You can control the temperature with a sensor and heater at the heat exchanger, monitor and control the gas flow, AND have an extra sensor channel to measure sample temperature.

NEW Magnet power supply - Best in class stability performance and optimised for accuracy and low noise.

New Oxsoft IDK instrument development kit software - With the new Oxsoft IDK, you have new levels of control. You can design remote control and configuration programs and integrate your system into your preferred experiment control architecture.

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